Electric discharge tube



Nov. 8, 1932.

P. R. DIJKSTERHUIS ELECTRIC DI SCHARGE TUBE Popko Remder Dkeerhusttorneg Patented Nov. 8,1932

UNI'IEDV STATES PATENT OFFICE Torno BEINDEH DIJxsTEnHUIs, or EINDHOVEN,NETHERLANDS, AssIGNoa To N. v. ,PHILIrs eLoEILmrENEABaIEHEN, orEINDHOVEN, NETHERLANDS ELECTRIC DIscHAneE TUBE Application illedDecember 11, 1924, Serial No. 755,274, and in the Netherlands January15, 1924. Renewed November 10, 1980.

The resent invention relates to the attachment o electrodes in electricdischarge tubes, more particularly to the attachment of the incandescentcathode, the anode and one or more grid shaped electrodes in dischargetubes.

Usually, the cathode is made in the shape of an elongated V, the twosides of the V being connected to the leading-in wires, and the apex ofthe V being connected to a'metallic hook which is secured to andinsulated from another electrode.

A spring made of tungsten or similar material, is frequently used tokeep the filament rigidly stretcheds It has however been found that sucha spring loses its tension in course of time and therefore in theconstruction according to the invention a spring is preferably omitted.

It has, moreover, been found that the insulating `material to which thehook is secured, ecomes more or less conductive owing to the hightemperatures to which it is y exposed, and it also occurs frequentlythat the material which is disintegrated or which volatilizes from thefilament, precipitates on the insulating material in such a degree'thatVconduction may occur along the surface of the said material.

An object of the invention is to protect the insulating material fromexcessive heat, because at high temperatures the insulating material maybecome conductive. Another' ob- ]ect of the invention is to shield theinsulating material from the hot filament in order to prevent anyvolatilized matter from the filament from being precipitated on theinsulating material. y p c According to the invention a screen isarranged for this purpose between the cathode and the material by meansof which the supporting or suspending device of the cathode is attachedso as to be insulated from the` members which carry the current.

Between the points of attachment the incandescent cathode is preferablysuspended to or supported by one or more metal hooks which are securedto one or more supporting devices with the aid of insulating material.

or hooks may be secured to one or more supporting ieces made of quartzor similar material; t esepieces are supported by metal members whichare connected to another electrode and the hook or hooks are led throughone or 4more apertures provided in a plate which likewise is secured tothe other electrode.

According to the invention, in a discharge tube like the oneabovementioned, comprising an anode and a grid and in which theelectrodes are arranged concentrically, the grid supports or theirextensions may be provlded with transverse rods carrying little tubesmade of quartz or similar material whilst .the hook or hooks forsupportin the cathode is or are attached to the said tu es by means of aclamp or a resilient connection. The resilient connection serving forthe attachment of ahook is preferablyan S-shaped plate.

In discharge tubes according to the invention it is of great importancethat means are provided for keeping the other electrodes so rigid intheir places that a displacement of the electrodes relative to eachother during the operation of the discharge tube cannot occur. Accordingto the invention the anode or another electrode which does not act as acathode, is attached for this purpose to a re-entrant glass tube, bymeans of a number of supports, the ends of which are secured to a closedor open ring which is arranged around the glass tube at some distancefrom the end; the supports are `provided in this case with lateral armsthe ends of which are sealed into the end of the glass tube.

If two grid-shaped electrodes have to be arranged in the discharge tube,they may be attached according to the invention on one side to are-entrant glass tube, whereas their other ends are kept spaced at therequired distance from each other by means of an insulating connection.

According to the invention the supports of 'each of the grid-shapedelectrodes may fur- 'o 'According to the invention the metal hook thelike.- According to the invention the ends 100 tween the filament ofeach pair of supports may be located in one line and may be connected toeach other by means of a straight piece of a tube made of quartz orsimilar materiah The accompanying drawing illustrates by way of examplea construction of a discharge tube comprising` an incandescent cathodeaccording to the invention. In the said drawing: Figure 1 is anelevation of a discharge tube comprising an incandescent cathode, andanode and two grid-shaped electrodes.

Figure 2 is a detail View showing the attachment of the hook lof thefilament to the tubes made of quartz.

Figure 3 is a detail view showing the attachment of the anode to are-entrant glass tube.

Figure 4 is a plan of the plate located bcand the securing device ofthehook which supports the filament.

The discharge tube shown in the drawing, is formed by a glass bulb 1 towhich a twice bent glass tube 2 is hermetically sealed.

Leading-in wires 4 and 5 for a cathode 6 are hermetically sealed intothe clamped portion of the innermost glass tube 3. The cathode 6 has theshape of an elongated V and is suspended at its apex to a metal hook 7which is attached to an S-shaped plate 8 (see Figure 2) which clampsitself elastically on to tubes 9 and 10 which are made of quartz andthrough which pass little rods 11 and 12.

The hook 7 passes through an aperture provided in a metal plate 16 whichis carried by a grid-shaped electrode 15. Thls plate protects the quartztubes 9 and 10 from being heated too high by theilament whilst at thesame time it intercepts the material volatilized from the ilament.

The rods 11"-and 12 are secured to lengthening pieces or extension rodsof supports 13 and 14 of the grid-shaped electrode 15 which consists ofa metal Wire helically wound on four supports, only two being shown inthe drawing. The other ends of these supports are connected to aresilient clamp 19 which may be of any known construction and which isslid on the end of the glass tube 2. A leading-in wire 17 for theelectrode 15 is secured to the metal c1amp119 and is hermetically sealedinto a little tube 181.

A second grid-shaped electrode 20 is concentrieally arranged around thecylindrical electrode 15. The electrode 2O also consists of a metalports, only ing shown. Encircling said supports and secured thereto aremetal rings 28 and 29. These supports are connected at one end to aflexible metal plate 23 which is clamped on to the tube 2 by means of aspring plate 24. A wire 25, the end of which is connected Vto a clamp 24and which is hermet-ically sealed into a glass tube 41, serves forcarrywire helically wound on four sup-v two such supports 21 and 22 behing the current to the electrode 20. The

other ends of the electrode supports 21 and y 22 .are provided withextension rods which of, a hook so that the lengthening-pieces 0r arebent in the shape ends are brought into alignment with the extensionrods of the supports 13 and 14 of the auxiliary electrode similar tothat shown and described for supports 13, 14 and 21, 22.

A cylindrical anode 30 is arranged around the electrode 20 and iscarried by four supports 31, 32, 33 and 34, the lengtheningpieces orextension rods of which are secured to a metal ring 35 which is arrangedloosely around the re-entrant glass tube 36. The four supports arefurther secured to lateral arms 37, 38, 39 and 40 which are sealed intoa clamped portion or press, commonly socallcd, at the end of the tube36. f Although it is not necessary to lead all these four arms throughthe glass and it would be satisfactory to lead only one wholly throughthe glass it is advisable to make use of the construction shown in thedrawing because in this case a very rigid attachment of the electrode isobtained.

It must be observed, in addition, that the discharge tube according tothe invention is preferably so arranged during its operation that thetop of the filament hangs down as is shown in the drawing. If during theoperation the incandescent cathode becomes hot and expands, the apex ofthe cathode in the hook 7 is free to move downwards so that the cathodewire is prevented from being distorted.

lVhat I claim is rl. A -discharge tube having a plurality of electrodesincluding a cathode and at least one grid with its supports, said gridsupports having transverse rods of insulating material, and. hooks tosupport the cathode, said hooks being attached to the transverse rods bymeans of a resilient S shaped plate.

2. A discharge tube having a plurality of electrodes including a cathodeand at least one grid with its supports, said grid supports avingtransverse rods of quartz, and hooks to support the cathode, said hooksbeing attached to the transverse lrods by means of a resilient S shapedplate.

3.v A discharge tube having a cathode and at least one other electrode,said other electrode being fastened to supports, the ends of thesupports being secured to a ring arranged around a reentrant glass tube,said ring being llt) assumes positioned at a distance from the end 0fthe tube, and lateral arms extending from said supports, the ends ofthese arms being sealed into the end of the reentrant tube.

4. In a discharge tube having a cathode, plate and double grid, aplurality of rod supports secured at one end upon which one grid issupported, and a plurality of rod supports 'secured at one end uponwhich the other grid is supported, the free ends of the two sets` ofgrid supports being connected by means of insulators.

5. In a discharge tube having a cathode, plate and double grid, aplurality of'rod supports secured at one end upon which one grid issupported, a plurality of rod supports se- ,cured at one endvupon whichthe other grid is supported, the free end of each supporting rod of oneset of supports being bent so that the end is in alignment with one ofthe supports of the other grid, and an insulator securing the two endstogether.

6. In a discharge tube having a cathode,

`plate and double grid, a plurality of rod supports secured at one endupon which one grid is supported, a plurality of rod sup orts secured atone end upon which the ot er grid is supported, the free end of eachsupporting rod of one set of supports being bent so that the end is inalignment with one of the supports of the other grid, and quartz tubessecurmg the two ends together.

A discharge tube comprising an anode, cathode, and grid, a tensioningmember for the cathode, an S-shaped plate, the tensioning v

